The Panthers are holding their breath, after one of their most important players went down during this morning’s work with the Dolphins.

Panthers coach Ron Rivera told reporters afterward that Benjamin suffered “a sprain” during practice this morning, and was headed back to Charlotte to have an MRI on his left knee.

While that might be construed as positive, the slow-motion video of Benjamin collapsing (via Bill Voth of Black and Blue Review) shows that it was a non-contact injury, and that’s never a good sign.

The Panthers felt confident about their receiving corps this year based largely on Benjamin’s breakout rookie season, in which he caught 73 passes for 1,008 yards and nine touchdowns.

They brought back Ted Ginn this offseason, and Charlotte’s the one place he’s looked like an actual NFL wide receiver. But if Benjamin is out any amount of time, they’re going to need 2015 second-rounder Devin Funchess to play an immediate role.